This invention relates generally to beverage preparation systems, and more particularly concerns automated systems for preparing and pasteurizing soft drink beverages.
Systems for preparing and packaging soft drinks in bottles or cans have usually omitted a pasteurizing station. The feedstock beverage syrup conventionally possesses a sugar content of at least about 32.degree. Baume; and a product of this elevated sugar content will not support microbiological growth. In practice, the beverage syrup is not diluted to a level where contaminant organisms might proliferate until immediately prior to carbonation and package filling. Thus, in many soft drink beverage preparation systems, pasteurization has not been required.
In some circumstances, however, pasteurization has been found desirable or essential. In many emerging nations, the demand for carbonated drinks and the like is of very recent origin, and experienced preparation and packaging personnel are not available. Too, sugar supplies are frequently of variable quality in these areas.
But care must be taken when pasteurizing any liquid, and these precautions can become especially important when pasteurizing soft drink fluids. If the fluid is not sufficiently heated, complete pasteurization may not occur and a potentially impure product can be produced. On the other hand, overheating the beverage can accelerate the oxidization of flavor essences, and can cause unwanted beverage coloration darkening because of sugar carmelization.
Another source of difficulty arises in applying pasteurizing systems to soft drink beverage processing systems. Various machines in the main soft drink processing system or line must often be rapidly started and stopped. This starting and stopping place causes great fluctuations in fluid flow rates in the system. All the system components, including the pasteurizing apparatus must be able to handle these rapid fluctuations in fluid flow rates without damage or malfunction.
To accommodate rapid fluid flow rate changes, some soft drink pasteurizing systems have employed means providing return circulation of the pasteurized beverage to the fresh product inlet. This recirculation flow control can aggravate color and flavor problems and, depending upon the point at which the pasteurized product is fed back into upstream portions of the system, can introduce a possible source of microbiological contamination. In addition, delivery of hot product to relatively cool upstream apparatus is a potential source of apparatus malfunction. The apparatus described and claimed in U.S. patent application Ser. No. 155,301 filed June 2, 1980 overcomes many of these problems.